1. Field
The present invention relates to a liquid droplet ejection device, a liquid droplet ejecting method, and an inkjet recording apparatus.
2. Description of the Related Art
Inkjet recording apparatuses usually have been known as image forming apparatuses such as printers, facsimile machines, copiers, multifunction peripherals (MFP), etc. In the inkjet recording apparatus, an inkjet recording head, which includes nozzles to eject ink droplets, pressure chambers communicating with the nozzles, and piezoelectric elements to compress the ink in the pressure chambers, and form desired characters and figures on recording media (paper, metal, wood, and ceramics).
The ink in the pressure chamber is exposed to external air via the openings of the nozzles, which increase the viscosity of (thickens) the ink. In a proposed inkjet recording apparatus, by applying a slight vibration to meniscus (ink surface), the increase in the viscosity of the ink positioned near the openings of the nozzles, and ejecting the ink droplet is made stable. For example, see JP-2000-037867.
In addition, a technique in which ejection failure of the nozzles is avoided by discharging the ink whose viscosity has thickened is proposed. For example, there are a star-flushing technique where ink droplets having a size much smaller than visible in image forming regions and a line-flushing technique where ink droplets are ejected at constant intervals in no-image-forming regions.
In order to reduce running cost of an inkjet recording apparatus having a liquid ejecting device installed, it is necessary to alleviate the consumption of the ink.
However, in the conventional inkjet recording apparatus, even when the viscosity of the ink positioned near the openings of the nozzles has a suitable viscosity, ink droplets are discharged from all the nozzles. Therefore, the apparatus consumes ink wastefully, thereby adversely increasing the running cost.